Multistand universal rolling mills

ABSTRACT

A roll stand is provided for multistand rolling mills such as wire rod mills having interchangeable stands in which a roll stand is provided with an input shaft adapted to be driven by an external drive means, an intermediate shaft is provided in said stand driven by said input shaft, said intermediate shaft driving rolls in said stand and connected to the input shaft by intermediate gears having a gear ratio adjusted to the diameter of the rolls whereby the peripheral speed of the rolls is uniform in any given stand regardless of roll diameter.

O United States Patent m1 [72] inventor All Bindernagel 5 R f r c Cited Germany P 818397 382,017 5/1888 Tasker 72 249 x [22] Filed Apr. 23, 1969 2,214,279 9/1940 Kocks. .4 72/224 X [45] Patented June 15, 1971 2,950,934 8/1960 Uebmg 72/224 X [73] Assgnee 3 I8] 332 s 1965 v D 1 72/249 [32] Priority May 2 9 9 y om Ofp eta [33] Germany Primary Examiner-Milton-S. Mehr [3] I Pl,752,283.7 Attorney- Buell, Blenko & Ziesenheim ABSTRACT: A roll stand is provided for multistand rolling mills such as wire rod mills having interchangeable stands in [54] rg g g g Q YP ROLUNG MILLS which a roll stand is provided with an input shaft adapted to be a rawmg driven by an external drive means, an intermediate shaft is [52] US. Cl 72/224, provided in said stand driven by said input shaft, said inter- 72/249 mediate shaft driving rolls in said stand and connected to the [5]] Int. Cl B2lb 13/10, input shaft by intermediate gears having a gear ratio adjusted B21b 35/00 to the diameter of the rolls whereby the peripheral speed of [50] Field of Search 72/249, the rolls is uniform in any given stand regardless of roll diameter.

MULTISTAND UNIVERSAL ROLLING MILLS This invention relates to multistand universal rolling mills and particularly to wire rod mills with three nonadjustable rolls per stand.

The roll life in rolling mills, particularly rod mills is determined by the duration of the usability of a given roll pass. In the case of nonadjustable rolls, their life for a given pass terminates when, as a result of wear through use, they no longer produce a product within accepted tolerances. When this occurs the rolls are no longer usable and must be reworked to a larger size pass.

Rolling mills with adjustable rolls for adjusting and correcting the required pass openings are known. This, of course, increases the life of the rolls for a given pass. Unfortunately this advantage induces several disadvantages which generally override the value to be attained by adjustability. The roll adjustment is difficult and expensive to achieve, and the rolled product is less exact in its toleranced dimensions than is the case with nonadjustable rolls.

It is also well known, to open up a used pass to the next larger pass size with the same nominal roll diameter, in order to extend the roll life. This way, roll stands move up from the smallest finishing pass position step by step to the entry pass. Using this method, it is only possible to open up a used roll set to the next larger pass size. The same roll cannot be used again with the same pass size. Another disadvantage is, that the smaller passes wear out more rapidly than the larger passes. The result is a great variation of the roll life for the individual roll sets in a rolling mill, which requires a more frequent replacement of the smaller passes. A greater utilization and, thus, a longer roll life cannot be achieved with the methods heretofore known and practiced.

The present invention solves the problems of maximum utilization of rolls and overcomes the disadvantages inherent in all of the prior art practices. By the practices of the present invention, the rolls of a rolling mill can be used much longer and can be placed in any roll stand position and as many times as the operator desires.

The invention provides that worn out rolls which have been made usable again through remachining but which now have a different diameter, are placed in new roll stands which are equipped with a proper intermediate gearing according to the different roll diameter. A specially designated interchangeable stand with an intermediate gearing is used as a new stand for three such worn out rolls which were remachined to a new pass dimension instead of a normal rolling mill stand. The interchange stand is built to the necessary dimensions to suit the different roll diameters, but has the same central input shaft as all the normal stands. A characteristic of'all stands is that always three rolls in an interchangeable stand are driven by an unchanged centrally driven intermediate gear, with a speed changed according to the different roll diameter and center distance of the roll shafts. A change in the angular velocity of the rolls, which is required on account of the different roll diameter, is thus achieved.

Rolls with a different diameter located in the interchangeable stand can be used several times in the same or another stand location, whatever is of more advantage. According to the prevailing requirements, the rolls can be provided one or several times with the same original pass size, be placed in the proper dimensioned interchange stands, and used at the right stand location in the rolling mill. Any rolls changed in diameter will only be used in the proper interchange stands.

It is further possible to machine the same pass dimension several times in to the roll circumference. It is also anticipated, that different pass dimensions can be machined in the roll circumference in proper sequence. Therefore. it is possible to provide the same rolls in proper sequence with new and larger pass dimensions of the same or of different size, once or several times as desired and to use these rolls with the proper interchange stands at the designated stand locations.

In the foregoing general statement of my invention I have set out certain objects, purposes and advantages of my invention. Other objects, purposes and advantages will be apparent from a consideration of the following description and the accompanying drawings in which:

FIG. I is a section of a roll showing; the original and a new roll dimension;

FIG. 2 is a section through an interchangeable stand according to my invention with an intermediate gear drive and three rolls with a new dimension.

Referring to the drawings and particularly to FIG. 1 in the first instance roll 1 with the roll axis 2- is originally made to a large diameter as indicated by radius a and the chain line outline is provided with the original pass dimension 4 for the rolled product 5 at the circumference. The roll body 3 can I consist completely or partially of wear resistant or other suitable materials. Always three such rolls 1 are placed into a roll stand and used together with the stand at the designated stand position in the rolling mill. Worn out and used original pass dimensions 4 are replaced by machining new pass dimensions 6 into the rolls 1. Optionally, the same roll 1 can be provided with the same or another new pass dimension 6 whereby roll 1 now has a radius b according to the new and different diame ter. This change of the roll diameter also changes the speed of the rolled product 5 at the new pass dimension 6 in an undesired manner, when using the same drive for the rolls 1. In order to correct this speed difference, three rolls 1 machined to a new suitable diameter are placed into an interchange stand 7 with the same center input shaft as the normal stands, but provided with an intermediate gear 8. The intermediate gear 8 is designed in such a way that the rolls I are arranged to centerline rolling 9 having the distance b to the roll axis 2 according to the different roll diameter, and that the rolls are running at a different speed according to the new pass dimension 6. In order to keep the central drive unchanged, it is of advantage to provide an input shaft or the like 10 at the interchange stand 7. Form, arrangement and use of interchange stand 7 with intermediate gear 8 therefore make it possible for the rolls 1 to operate always at the right speed suiting the new machined pass dimension 6.

By using interchange stands 7 with the intermediate gears 8 it has become possible to machine new pass dimensions 6 of the same or of different size and as many times as desired into the circumference 3 of rolls 1 and to use this stand at the designated stand position in the rolling mill. It is of special advantage that the pass dimension 4 or 6 can be machined several times anew into the same roll 1. This is of substantial importance especially for the smaller passes as experience has shown. Depending only on the condition of the circumference zone 3, any roll 1 can be provided as many times as desired with a new pass dimension 6 and accordingly, be placed in.

operation in the rolling mill. The usability and the life of the rolls is substantially increased on one hand, while on the other hand, a substantial decrease in expenditure is attained.

While I have illustrated and described certain preferred practices and embodiments of my invention in the foregoing specification it will be understood that this invention may be otherwise embodied within the scope of the following claims.

I claim:

I. In a multistand rolling mill such as a wire rod mill with three nonadjustable rolls per stand driven by an input shaft connected to an external drive means the improvement comprising at least one interchangeable roll stand interchangeable with each stand of said rolling mill, an input shaft in said interchangeable stand adapted to be driven by said external drive means, an intermediate shaft in said stand driven by said input shaft, said intermediate shaft driving said rolls and connected to the input shaft by intermediate gears having a gear ratio adjusted to a preselected smaller diameter of the rolls whereby the peripheral speed of the rolls is uniform in any given stand regardless ofdiameter ofthe: rolls.

2. A multistand rolling mill such as a wire-rod mill comprising a housing adapted to receive a plurality of successive interchangeable roll stands each carrying three nonadjustable rolls, an input shaft in each stand driving said rolls, drive means in the housing drivingly engaging said input shaft, at least one replacement roll stand interchangeable with each of said roll stands having an intermediate shaft driven by said input shaft and driving said rolls, said intermediate shaft connected to said input shaft by intermediate gear having a gear ratio adjusted to a preselected smaller diameter of the rolls whereby said rolls when worn can be machined to said smaller preselected diameter and the peripheral speed of the smaller diameter rolls and the pass opening are uniform in any given stand regardless of roll diameter.

3. A rolling mill stand for multistand wire mills having nonadjustable rolls adapted to use rolls which have been cut to smaller than normal diameter comprising a generally annular housing, an input shaft in said housing, an intermediate shaft in said housing, three spaced rolls journal sets in said housing receiving said smaller rolls, means connecting said smaller rolls to said intermediate shaft, and intermediate gear means connecting said input and intermediate shafts and having a gear ratio adjusted to the diameter of the rolls whereby the peripheral speed of the rolls and the pass opening are controlled to selected values.

4. The method of reworking worn rolls for multistand wire rod mills and the like having nonadjustable rolls comprising the steps of a. machining three rolls from a stand to a uniform'smaller diameter;

b. mounting said rolls in a mill stand having an input shaft and an intermediate shaft drivingly connecting said rolls; and

c. interconnecting said input and intermediate shaft with gearing having a ratio such that the peripheral speed of the machined rolls of small diameter is the same as that of the original rolls. 

1. In a multistand rolling mill such as a wire rod mill with three nonadjustable rolls per stand driven by an input shaft connected to an external drive means the improvement comprising at least one interchangeable roll stand interchangeable with each stand of said rolling mill, an input shaft in said interchangeable stand adapted to be driven by said external drive means, an intermediate shaft in said stand driven by said input shaft, said intermediate shaft driving said rolls and connected to the input shaft by intermediate gears having a gear ratio adjusted to a preselected smaller diameter of the rolls whereby the peripheral speed of the rolls is uniform in any given stand regardless of diameter of the rolls.
 2. A multistand rolling mill such as a wire rod mill comprising a housing adapted to receive a plurality of successive interchangeable roll stands each carrying three nonadjustable rolls, an input shaft in each stand driving said rolls, drive means in the housing drivingly engaging said input shaft, at least one replacement roll stand interchangeable with each of said roll stands having an intermediate shaft driven by said input shaft and driving said rolls, said intermediate shaft connected to said input shaft by intermediate gear having a gear ratio adjusted to a preselected smaller diameter of the rolls whereby said rolls when worn can be machined to said smaller preselected diameter and the peripheral speed of the smaller diameter rolls and the pass opening are uniform in any given stand regardless of roll diameter.
 3. A rolling mill stand for multistand wire mills having nonadjustable rolls adapted to use rolls which have been cut to smaller than normal diameter comprising a generally annular housing, an input shaft in said housing, an intermediate shaft in said housing, three spaced rolls journal sets in said housing receiving said smaller rolls, means connecting said smaller rolls to said intermediate shaft, and intermediate gear means connecting said input and intermediate shafts and having a gear ratio adjusted to the diameter of the rolls whereby the peripheral speed of the rolls and the pass opening are controlled to selected values.
 4. The method of reworking worn rolls for multistand wire rod mills and the like having nonadjustable rolls comprising the steps of a. machining three rolls from a stand to a uniform smaller diameter; b. mounting said rolls in a mill stand having an input shaft and an intermediate shaft drivingly connecting said rolls; and c. interconnecting said input and intermediate shaft with gearing having a ratio such that the peripheral speed of the machined rolls of small diameter is the same as that of the original rolls. 